The assassination attempt on Rep. Gabrielle Giffords over the weekend prompted lawmakers on Sunday to blame, in part, the nation’s political rhetoric as overheated and also push such issues as congressional security and gun-control laws.

“We need to stop, pause and reflect,” Sen. Lamar Alexander, Tennessee Republican, said just hours after leaders of the Republican-controlled House announced there will be no votes this week in the chamber, including one scheduled to repeal the health care law.

The man accused being the gunman, 22-year-old Jared Lee Loughner, has been linked to Internet postings about reading the works of Adolf Hitler and Karl Marx, but there are no official comment on a motive in the shootings Saturday at a Tucson, Ariz., shopping center in which six people were killed and 14 others injured.

“We live in a world of violent images and violent words,” said Sen. Richard J. Durbin, Illinois Democrat. “But those of us in public life and the journalists who cover us should … try to bring down the rhetoric, which I’m afraid has become pervasive in our discussion of political issues. The phrase ‘don’t retreat, reload,’ putting cross hairs on congressional districts as targets … invite the kind of toxic rhetoric that can lead unstable people to believe this is an acceptable response.”

Both Mr. Durbin’s phrases referred to Mrs. Palin, who exhorted conservatives back in March via her Twitter and Facebook accounts “don’t retreat, instead - reload” in all capital letters after the health care bill passed.

The “cross hairs” reference was to a map she put up months ago that targeted Mrs. Giffords and 19 other lawmakers for defeat over their votes in favor of President Obama’s health care plan. Mrs. Palin’s SarahPAC site took down the map.

There is no evidence from Mr. Loughner’s political postings on the Internet or any official word that he had seen the Palin map or phrase or wanted to punish Mrs. Giffords specifically over the health care bill.

Mrs. Giffords, a moderate Democrat in Republican-leaning Arizona, won her third term in November in a close race.

For her part, Mrs. Palin offered “my sincere condolences” Saturday “to the family of Rep. Gabrielle Giffords and the other victims of today’s tragic shooting in Arizona” and a spokesman took to the airwaves Sunday to deny any link to the shooting.

“We have nothing whatsoever to do with this,” Palin aide Rebecca Mansour said Sunday in an interview with radio host Tammy Bruce.

Despite the contention, politicians in both parties pulled together to praise their colleague and trim back much of their own politicking in favor of more somber actions.

House Speaker John A. Boehner of Ohio told lawmakers in a conference call Sunday to “pull together as an institution,” and the flag over the U.S. Capitol was at half-staff.

“What is critical is that we stand together at this dark time as one body,” he said. “We need to rally around our wounded colleague, the families of the fallen, and the people of Arizona’s 8th District. And, frankly, we need to rally around each other.”

President Obama called for a national moment of silence at 11 a.m. on Monday, saying, “It will be a time for us to come together as a nation in prayer or reflection, keeping the victims and their families closely at heart.”

Mr. Obama and House Minority Leader Nancy Pelosi, California Democrat, were among the lawmakers to cancel planned stump appearances.

But the effort to score political points precisely over political rhetoric continued Sunday.

House Minority Whip Steny H. Hoyer, Democratic minority whip, said everybody, including members of Congress, must be aware that their words have consequence, but appeared to put the news media at the top of his list.

“Far too many broadcasts now in so many outlets have the intent of inciting and inciting people to opposition, to anger, to thinking the other side is less than moral,” he said on CBS’ “Face the Nation.”

“I think we need to all take cognizance of that and be aware that what we say can, in fact, have consequences.”

Mr. Alexander cautioned during his appearance with Mr. Durbin on CNN’s “State of the Union” that “we have to be very careful about imputing the motives or the actions of a deranged individual to any particular group of Americans who have their own political beliefs.”

He noted Mr. Laughner’s barely coherent and paranoid political writings are “not the profile of a typical tea party member, if that’s the inference that’s being made.”

Republicans also pointed out Sunday that martial metaphors are common in politics on all sides. For example, Mr. Obama said during the 2008 presidential campaign, “If they bring a knife to the fight, we bring a gun.”

Meanwhile Sunday, Rep. James E. Clyburn, South Carolina Democrat, brought a budget angle to the table, saying that Republicans should not cut House members’ budgets as planned because more money for security might be needed.

Mr. Clyburn said on “Fox News Sunday” that House leaders should look at congressional members’ security and personal spending accounts “rather than cut, cut, cut.”

The Republican-controlled House voted last week in favor of cutting the chamber’s operating budget by 5 percent, which is expected to save roughly $35 million. The vote will trim the roughly $1.5 million budget for each of the chamber’s 435 members by roughly $75,000, which will likely result in smaller staffs.

Speculation also centered on whether Mrs. Giffords may have been targeted because she is Jewish and the Anti-Defamation League put out a statement.

But everybody associated with Mrs. Giffords remarked on her low-key style of compromise.

“She is not only an extraordinary public servant, but she is also somebody who is warm and caring,” Mr. Obama said. “She is well liked by her colleagues and well liked by her constituents.”

Rep. Chris Van Hollen, Maryland Democrat, on ABC’s “This Week” said: “Gabby Giffords was a role model. She was a person who was passionate about issues but very even-tempered in her approach to things.”

He was joined on Fox by Rep. Cathy McMorris Rodgers, Washington Republican, who lauded the work of federal law enforcement, including the Capitol Police, whom she said advise congressional members on security issues before they go home for community events like the one at which Ms. Giffords was shot.

Rep. Debbie Wasserman Schultz, Florida Democrat, said lawmakers may have to retreat behind tighter security. Mrs. Giffords was shot at a publicly announced “Congress on Your Corner” event at a Tucson supermarket where residents could walk up to her and ask her questions.

“I think it needs to be a wake-up call for members who have treated … their own personal security in a cavalier way,” she said on NBC’s “Meet the Press.”

Mrs. McMorris Rodgers also said the burden of responsibility is on members of Congress.

“We as lawmakers must be more careful,” she said.

William Pickle, a former sergeant-at-arms in the U.S. Senate, said being in public office has become increasingly dangerous but acknowledged the federal government doesn’t have the money or ability to eliminate every attack.

“These things are impossible to stop,” he said on CNN.

Still, other lawmakers said such events are too valuable to be dispensed with.

“I like to look at people eye to eye, to see what they really believe and what they’re thinking,” Rep. Paul Broun, Georgia Republican, told reporters. “That is immensely helpful to me as an elected official. And if someone actually takes the time to come to an event, that carries extra weight.”